Chickpea, are you going to be stationed mainly in Rotovegas or travelling round afterwards?? Reason for asking is..you can bike from town to Whaka, it's only 5k's..That is unless you're doing some sort of enduro of course .
otherwise, yep most folks just rent a campervan-cheapest one i know of in Aust/NZ is Wicked campervans(you know the ones with the odd graffiti on them..)
Mmmmm..whaka..mmmmm..oooo...mmm....drool..